High-Order Harmonics and Isolated-Attosecond Pulse Generation of Three-Dimensional H Atom by UV-Assisted Chirped Fields

Authors

  • Hong-Dan Zhang Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
  • Jing Guo Aimer Human Engineering Research Centre, Beijing Institute of Fashion Technology, Beijing 100029, China
  • Hui-Ying Zhong Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
  • Xiang-Yi Luo Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
  • Hui Du Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
  • Yan Shi Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
  • Xuri Huang Institute of theoretical chemistry, Jilin University, Changchun 130012, China
  • Xue-Shen Liu Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China

DOI:

https://doi.org/10.4208/jams.022016.041316a

Keywords:

High-order harmonic generation, generalized pseudospectral method, UV-assisted chirped fields, attosecond pulse.

Abstract

By solving the time-dependent Schrödinger equation (TDSE) accurately with time-dependent generalized pseudospectral (TDGPS) method, we theoretically investigated the high-order-harmonic generation (HHG) from three dimensional (3D) Hydrogen atom in ultraviolet (UV)-assisted chirped fields. When a 128 nm UV pulse is added on a chirped fundamental field, the HHG spectra is greatly broadened and enhanced, which is quite similar as the HHG from H atom initially prepared in the first excited state in the chirped field only. Besides, the HHG of H atom in the combination of a chirped fundamental field and a 256 nm UV pulse case is also investigated. The HHG process is illustrated by the semi-classical three-step model and the time-frequency analysis. The ionization probability and electron wavepacket as functions of time are also calculated to further illustrate this phenomenon. Furthermore, we also discuss the influence of time delay between the chirped fundamental field and the 128 nm UV pulse on HHG process. Finally, by superposing the harmonics in the range of 200th-260th order, an isolated attosecond pulse with a duration of about 64 as can be generated.

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Published

2016-07-01

Issue

Vol. 7 No. 3 (2016)

Section

Articles